This invention relates to a control apparatus for controlling passenger conveyers such as escalators and motor-driven passageways by use of an electronic computer, for example a digital electronic computer.
Currently, the dominant control means for a passenger conveyer is a sequence control apparatus composed of relays. An example of the control apparatus formed by a digital computer is the "passenger conveyer safety equipment" disclosed in JP-A-55-11402. The prior-art control apparatus of this type which uses a digital electronic computer for the control of passenger conveyers will be described in the following discussion.
The control apparatus for a passenger conveyer whose stroke is inclined, that is to say, an escalator will be taken up as an example.
Referring to FIGS. 1 and 2, the escalator has driving sprocket 1 and a driven sprocket 2 installed in the top and bottom machine rooms R1 and R2, respectively. Footstep chains 3 are wound around the sprockets 1 and 2 to form endless loops. Footsteps 4 are attached in a line to the endless chain 3. This assembled body is driven by a driving machine 5 through an intermediary of driving chains 6 and the driving sprocket 1. A guide rail 7 guides the footsteps 4. Handrails 8, driven at the same speed as the footsteps 4, run on railings 9. The intermediate section between the footsteps 4 and the railings 9 is covered by skirt guides 10. On the other hand, the driven sprocket 2, pulled by springs 11, pulls the footstep chains 3.
In the escalators as described above, two sets of safety switches are provided, one for preventing passengers from being caught by the escalator and the other for securing safety for the passengers by stopping immediately when the machine breaks down.
The former safety switches are installed in the gap between the running section and the fixed section, in the regions where there occurs a difference in the relative motion of the footsteps, for example. The former safety switches include inlet switches 13 (four in total; at left and right of the top and bottom positions) which are actuated when a foot or a hand is drawn in at the inlet part 12 by the handrail 8; skirt guard switches 14 (four or more in total; at left and right of the top and bottom positions) are actuated when a foot or the like is caught between the skirt guard 10 and a footstep 4; and footstep safety switches 15 (two in total; at left and right of the top or bottom position) are actuated when a foot is caught by the relative motion of the footsteps 4.
The latter safety switches include a speed governor switch 21 which is actuated when the escalator exceeds a speed limit, a driving chain safety switch 22 which is actuated when the driving chain 6 breaks or is expanded over a specified value, and footstep chain safety switches 23 (two in total; at left and right). The footstep chain safety switches are provided to. detect an abnormality in which the footstep chains 3 are elongated, reducing the tension by the springs 11 to less than a predetermined value, making it impossible for the footsteps 4 to keep the predetermined space therebetween, to detect that a foreign substance is caught in the running path of the footsteps causing the chain 3 to be locked, and to detect that the chain 3 was broken.
In addition, emergency stop switches 31 and 32 are installed on the operation switch panels at the top and bottom positions of the escalator in order to effect artificially a stop in an emergency.
Further, on the operation switch panel are provided a switch for distinguishing between operating the escalator to move upwards and downwards and a switch for stopping the escalator, to be described later.
FIG. 3 is a general block diagram of a control apparatus to control the driving machine and switches. Electric power is supplied to the escalator through a circuit breaker 51, and led, through a termal relay 53 and contacts 55a, 57a of Up and Down change-over switches 55, 57, to the driving machine 5, in which the supply power is connected to a motor 59 and a brake 61. On the other hand, the power is supplied also to the control apparatus 63 through the circuit breaker 51. FIG. 4 is a detailed block diagram of the control apparatus 63.
Used as a digital electronic computer in FIG. 4 is a microcomputer. This microcomputer 81 is composed chiefly of a microprocessor (MPU) 83 as a central part, read only memory (ROM) 85, a random access memory (RAM) 87, peripheral interface adapters (PIA) 89, 91 and 93, and a clock pulse generator (CPG) 84 to provide clock pulses as a time base for operation timing of these devices.
A usable type of each of these devices is mentioned below and detailed description of them is omitted. For MPU 83, an HD6800 made by Hitachi can be used, and for PIA89, PIA91, PIA93, HD6821s made by Hitachi can be used. It ought to be noted that for ROM85 and RAM87, ordinary semiconductor memories are utilized, and for CPG84, an ordinary clock pulse generator is used. The operation of this CPG84 is such that clock pulses .phi.1 and .phi.2 are generated based on the frequency of a quartz oscillator, not shown, and when a source voltage, not shown, has become stable, the clock pulses .phi.1 and .phi.2 are provided to MPU83. Though not shown in FIG. 4, while the source voltage is not stable, reset signals are output to the respective devices to cause the contents of their registers to be initialized.
The general operation of the microcomputer 81 will now be described. When the source voltage for the microcomputer 81, clock pulses .phi.1 and .phi.2 are applied from CPG84 to the terminals .phi.1 and .phi.2 of MPU83, whereby MPU83 starts to operate, and MPU83 fetches an instruction and addresses involved in the instruction execution from ROM 85 in which the program is stored through an address bus 97 and a data bus 99 connected to terminals A and D of the devices. MPU83 decodes the instruction and executes processings according to the result of the decoding. The processings of MPU83 executes by reading data from RAM87 or a PIA or outputting data to those devices.
In the microcomputer 81, an additional timing signal is sent from the timer 101 to the IRQ terminal of MPU83, so that an interrupt occurs at the microcomputer 81 at fixed intervals, and each time an interrupt occurs, a particular program is executed. By counting the number of interrupts that have occurred, it is possible to know the elapsed time (time of the day).
What have been described are all directly connected to MPU83. The safety switches described earlier are connected to MPU83 indirectly through PIAs 89, 91, which will be described in the following.
A total of the 11 switches, including the skirt guard switches 14, inlet switches 13, driving chain safety switches 6, and footstep chain safety switches 23, are formed of differential transformers 107. The output of the differential transformers 107 is input to an analog multiplexer 109. To address inputs of the analog multiplexer 109 are connected outputs of the B port of PIA89. The analog multiplexer 109 selects the output of the 11 differential transformers 107 and inputs it to an A-D converter 113. The A-D converter 113 changes the analog input into digital signals. The A-D converter starts to convert analog signals into digital signals in response to a signal from the CA terminal of PIA89, and when the conversion is over, the converter in turn sends an end signal to the CA terminal of PIA89. When an end signal is sent to PIA89, normally the signal from the differential transformer 107 is stored once in RAM87 and then processed.
A switch 121 for upward movement, a switch 123 for downward movement, a stop switch 125 which have been mentioned before, an emergency stop switch 127, and the above-mentioned emergency stop switch 31 (one each of those switches is installed both at the top and bottom entrances, but only one each is illustrated as the representative ones.) and other switches 131, for example, are connected to the input terminal of PIA91.
The input of data to the microcomputer 81 has been described. As for the output, switches 55, 57 are connected with PIA93 through an output buffer 141. In addition, an alarm 143 for audible warning with lamp indication is connected to PIA93.
The microcomputer 81 periodically checks the ON/OFF states of the switches 107, 121, 123, . . . , 131 on the input side, and if there is no abnormality, the microcomputer 81 does nothing, and if abnormality is detected, it de-energizes the switches 55, 57. In other words, the microcomputer 81 energizes or de-energizes the switches 55, 57 according to the roles of the switches, and it also controls the alarm 143.